/* osgEarth
* Copyright 2025 Pelican Mapping
* MIT License
*/
#ifndef OSGEARTH_RANDOM_H
#define OSGEARTH_RANDOM_H 1

#include <osgEarth/Common>

namespace osgEarth { namespace Util
{
    /**
     * Psuedo random number generator. Results are guaranteed to be consistent across
     * machines given the same seed value.
     */
    class OSGEARTH_EXPORT Random
    {
    public:
        enum Method
        {
            METHOD_FAST        // not great, but super-fast and cheap.
        };

    public:
        /**
         * Constructs a new random number generator. It is seeded with
         * the system clock.
         * @param method RNG method to use
         */
        Random( Method method =METHOD_FAST );

        /**
         * Constucts a new random number generator with a user-specified seed.
         * The results are guaranteed to be globally consistent.
         * @param seed   RNG seed value
         * @param method RNG method to use
         */
        Random( unsigned seed, Method method =METHOD_FAST );

        /**
         * Copy constructor.
         */
        Random( const Random& rhs );

        /** dtor */
        virtual ~Random() { }

        /**
         * Seeds the PRNG with a new seed.
         */
        void seed(unsigned s);

        /**
         * Resets the PRNG to its initial state (initial seed).
         */
        void reset();

        /**
         * Gets the next random number as an unsigned int.
         * @param mod Modulus value. The result will fall within the range [0..mod)
         */
        unsigned next( unsigned mod );

        /**
         * Gets the next random number as a double in the range [0..1].
         */
        double next();

    private:
        Method   _method;
        unsigned _seed;
        unsigned _next;
    };
} }

#endif // OSGEARTH_RANDOM_H
